Does pes anserinus release affect outcomes in medial open wedge high tibial osteotomy?

Purpose: Medial open-wedge high tibial osteotomy (MOWHTO) is an effective treatment for medial compartment knee osteoarthritis. However, there is no consensus regarding the optimal management of the pes anserinus during the procedure. This study aimed to investigate the effects of pes anserinus release on radiological healing, alignment correction, and functional outcomes after MOWHTO.

Materials and methods: This retrospective cohort study included 73 patients who underwent MOWHTO with locking plate fixation. Patients were divided into two groups based on surgical preference: pes anserinus release (n = 35) and non-release (n = 38). Functional outcomes were assessed using the Knee injury and Osteoarthritis Outcome Score (KOOS) at baseline, six months, and 12 months. Radiographic parameters included the hip-knee-ankle (HKA) angle, medial proximal tibial angle (mMPTA), tibial slope, and time to bone union. Complications were also documented.

Results: Both groups were comparable in demographic characteristics and preoperative alignment. The non-release group achieved bone union significantly earlier (median 4.0 vs. 5.0 months, p = 0.019). There were no significant differences in HKA angle, mMPTA or tibial slope between the groups. At six months, KOOS scores were significantly higher in the non-release group (p < 0.001); however, by 12 months, both groups demonstrated similar functional outcomes. No major complications or nonunions were observed in either group.

Conclusions: Preserving the pes anserinus during MOWHTO does not compromise alignment correction and may enhance early bone healing and functional recovery. Routine release of the pes anserinus may be unnecessary, and its preservation could offer clinical benefits during the early postoperative period. Further prospective, randomized studies are needed to validate these findings.